Components utilized in industrial structures are frequently exposed to a corrosion environment and must be protected. For example, insulators utilized in electrical utilities such as suspension insulators in high voltage power transmission lines are designed to keep to a minimum, current discharge under normal conditions. However, when the insulator surface becomes contaminated, leakage current can develop along the surface of the insulator. The amount of this leakage current depends upon the voltage stress and conductivity of the film or contaminant on the surface of the insulator. The leakage currents can incur or cause arcing on the surface of the insulator which can have serious effects upon the insulator surface such as the formation of free carbon and non-volatile semiconductor materials. It may eventually result in a conducting path forming across the surface of the insulator and effectively shorting out the insulator.
The outer surface of the electrical insulator is the most important part of the insulator as this is the part that is subjected to the effects of electrical voltage stress, leakage currents and weathering. When the surface of the high voltage insulator is exposed to moisture such as rain or fog in combination with contaminated atmospheres as are found in industrial locations, the surface may be subject to extensive corrosion unless protected in some way from exposure to the corrosive atmosphere. Other potentially corrosive environments include along sea coasts where salt spray is found and in areas where agricultural chemicals are widely distributed.
More and more electrical utilities are switching toward the use of a one component room temperature vulcanizable (RTV) silicone rubber coating for these high voltage line sulators. By coating the surface of the insulator with the electrically non-conductive material, the coating provides for improved insulation that is arc resistant, hydrophobic and resistant to the stresses imposed upon such electrical insulators. This results in increased tin of the insulator between scheduled maintenance as well as increased overall life of the insulator. Examples of such coatings are shown for example in the applicant's prior U.S. patents and applications, specifically U.S. Pat. No. 6,833,407 issued Dec. 21, 2004; U.S. Pat. No. 6,437,039 issued Aug. 20, 2002; U.S. Pat. No. 5,326,804 issued Jul. 5, 1994; 2004/0006169 published Jan. 8, 2004 and 2003/0113461 published Jun. 19, 2003.
In addition to electric insulators, other components for industrial structures would also benefit from the automated application and method such as that of the present invention.
These insulators are manually coated on the ground and strung on the overhead transmission lines. This is not only labour and cost intensive, but also time consuming, especially for industrialized countries. Thus, there remains a need for a cost effective rapid method of coating a large number of insulators.